diff --git a/control/iosys.py b/control/iosys.py
index ce717c0fb..1bd9bcb9a 100644
--- a/control/iosys.py
+++ b/control/iosys.py
@@ -2242,7 +2242,7 @@ def ss(*args, **kwargs):
         Convert a linear system into space system form. Always creates a
         new system, even if sys is already a state space system.
 
-    ``ss(updfcn, outfucn)```
+    ``ss(updfcn, outfucn)``
         Create a nonlinear input/output system with update function ``updfcn``
         and output function ``outfcn``.  See :class:`NonlinearIOSystem` for
         more information.
@@ -2269,8 +2269,7 @@ def ss(*args, **kwargs):
         Everything that the constructor of :class:`numpy.matrix` accepts is
         permissible here too.
 
-    ``ss(args, inputs=['u1', ..., 'up'], outputs=['y1', ..., 'yq'],
-         states=['x1', ..., 'xn'])
+    ``ss(args, inputs=['u1', ..., 'up'], outputs=['y1', ..., 'yq'], states=['x1', ..., 'xn'])``
         Create a system with named input, output, and state signals.
 
     Parameters
diff --git a/control/passivity.py b/control/passivity.py
index 2ec1a7683..3777b3d92 100644
--- a/control/passivity.py
+++ b/control/passivity.py
@@ -281,7 +281,7 @@ def ispassive(sys, ofp_index=0, ifp_index=0):
     guaranteed to have an output of True (the system might not be passive with
     both indices at the same time).
 
-    For more details, see [1].
+    For more details, see [1]_.
 
     References
     ----------
diff --git a/control/sisotool.py b/control/sisotool.py
index 52c061249..781fabf40 100644
--- a/control/sisotool.py
+++ b/control/sisotool.py
@@ -213,6 +213,8 @@ def rootlocus_pid_designer(plant, gain='P', sign=+1, input_signal='r',
     derivative terms are given instead by Kp, Ki*dt/2*(z+1)/(z-1), and
     Kd/dt*(z-1)/z, respectively.
 
+    ::
+
           ------> C_ff ------    d
           |                 |    |
       r   |     e           V    V  u         y
diff --git a/doc/conventions.rst b/doc/conventions.rst
index 1832b9525..476366714 100644
--- a/doc/conventions.rst
+++ b/doc/conventions.rst
@@ -29,7 +29,7 @@ of linear time-invariant (LTI) systems:
 
 where u is the input, y is the output, and x is the state.
 
-To create a state space system, use the :fun:`ss` function:
+To create a state space system, use the :func:`ss` function:
 
   sys = ct.ss(A, B, C, D)